Two weeks on, a patient's pattern on a chart reads differently than you remember, and the note is a paragraph longer. You don't have to guess whether you changed it or whether it was always like that. Open the chart, click History, and the chart tells you how it got here.
What the drawer shows
History sits next to Undo and Redo in the chart editor. On a phone, Undo, Redo and History are behind the menu on the bottom bar. It opens a drawer on the right titled Session history, newest first, with a divider for each day. Every row has a label, the time, and the name of the team member who made the change. If that person's name can't be found, the row says Unknown.
The labels say what kind of write it was: Session saved, Status changed, Signed, Reopened after signing, or Restored. The top row of the list is marked Current version. When a save came from a bulk action rather than typing field by field, the row names it instead: Applied protocol followed by the protocol's name, Copied last session with that visit's date, or Cleared session. Those rows skip the itemized changes, since nearly every field moved at once.
What changed, in a line
Under each row, wherever there is an earlier version to compare with, a short summary lists what differs. Pattern changes read +Pattern or −Pattern with the names, points show as a count such as +2 points, techniques as +Moxa, and a retention-time change as 10→15min. Pulse and tongue read Pulse changed and Tongue changed, and a status change reads Status: draft → complete. A custom field shows by its label with the old and new value, like Pain level: 3 → 5.
Anything too long to fit on a line is a button. Notes changed, Pulse changed, Tongue changed and a long custom field expand in place: notes and long fields show the wording with additions and deletions marked word by word, and pulse and tongue list each position or attribute with its old and new value. Expanding is on demand, so a long history stays quick to scroll.
A long session doesn't bury the list
Autosave writes a row every time it saves, so a half-hour of charting is a lot of near-identical rows. Consecutive plain saves fold into one group, such as 5 saves with the time range, that you click to expand. A group ends at anything that isn't a plain save, such as a status change, a restore, a signature, or a gap of more than 10 minutes between saves. The footer of the drawer says so. Nothing is discarded: grouping is only how the list is drawn, and every save is still its own row when you expand it.
Going back, and signed charts
Every row except the current version has Restore this version, which loads that version into the chart and saves it forward as a new Restored row at the top. See restoring a version for what that keeps. Undo and redo walks the same saves one step at a time without opening the drawer.
On a signed chart the drawer still opens and still reads in full, but Restore this version is disabled, with a notice at the top that the session is signed and to unsign it first. Signing and unsigning are rows in the list themselves, so you can see who reopened a chart and when.